Gravitational pulsars: correlations between the electromagnetic and the continuous gravitational wave signal

TL;DR

This paper explores how next-generation gravitational wave detectors could observe correlations between electromagnetic signals and continuous gravitational waves from neutron stars, revealing insights into their internal physics and emission mechanisms.

Contribution

It provides a physical interpretation of potential correlations between electromagnetic and gravitational wave signals from pulsars, and discusses how future detectors can distinguish different internal models.

Findings

Next-generation detectors can differentiate models of superfluid coupling.

Timing noise origins can be constrained by gravitational wave observations.

Correlation analysis can reveal neutron star internal physics.

Abstract

Neutron stars emitting continuous gravitational waves may be regarded as gravitational pulsars, in the sense that it could be possible to track the evolution of their rotational period with long-baseline observations of next-generation gravitational wave interferometers. Assuming that the pulsar's electromagnetic signal is tracked and allows us to monitor the pulsar's spin evolution, we provide a physical interpretation of the possible observed correlation between this timing solution and its gravitational counterpart, if the system is also detected in gravitational waves. In particular, we show that next-generation detectors, such as the Einstein Telescope, could have the sensitivity to discern different models for the coupling between the superfluid and normal components of the neutron star and constrain the origin of timing noise (whether due to magnetospheric or internal processes). Observational confirmation of one of the proposed scenarios would therefore provide valuable information on the physics of gravitational wave emission from pulsars.